Prevalence of hypothyroidism among patients with isthmus-preserved thyroid lobectomy

Abstract

ObjectiveTo investigate the prevalence of hypothyroidism following thyroid lobectomy with isthmus preservation.MethodsThis retrospective, case series study included patients who had undergone thyroid lobectomy with preserved isthmus that was reversed onto the contralateral lobe. Neck ultrasound was performed in all patients and the patients were followed for 2 years.ResultsOut of 170 patients enrolled into the study, three were excluded due to preoperative hypothyroidism and one due to isthmusectomy; of the remaining 166 included in the final analyses, 139 patients (83.7%) were female, 27 (16.3%) were male, and patient age ranged between 17 and 77 years. The indication for intervention was thyroid swelling in 141 patients (84.9%). Final diagnoses following histopathological examination comprised benign lesion in 145 cases (87.3%), malignancy (follicular carcinoma and papillary thyroid carcinoma) in 12 cases (7.2%) and thyroiditis in nine cases (5.4%). During the 2-year post-surgery follow-up, 165 patients (99.4%) were euthyroid and one patient (0.6%) developed hypothyroidism.ConclusionPostoperative hypothyroidism following thyroid lobectomy appears to be very rare when the isthmus is preserved and reversed onto the contralateral lobe.

Predictive factors for hypothyroidy after hemithyroidectomy

“…Some authors studied the effect of isthmus-preserved thyroid lobectomy and found that the incidence rate of hypothyroidism after this surgery was lower. 16 To predict this complication, some authors established a risk-scoring system. One of these scores was established based on preoperative TSH level and age.…”

Predictive factors for hypothyroidy after hemithyroidectomy

“…Some authors studied the effect of isthmus-preserved thyroid lobectomy and found that the incidence rate of hypothyroidism after this surgery was lower. 17 …”

Comparison of the Incidence of Postoperative Hypothyroidism in Patients Undergoing Conventional Thyroid Lobectomy and Pyramid- and Isthmus-Preserving Lobectomy

“…Theoretically, subsequent levothyroxine therapy should not be required, because half of the total thyroid volume is preserved during thyroidectomy. However, in reality, 6.5–45% of patients develop hypothyroidism and require levothyroxine therapy [ 8 ]. There have been many studies on the hypothyroidism that develops following thyroid lobectomy, and it is thought to arise because of the inadequate remaining thyroid volume [ 6 ] or preoperative TSH concentration [ 5 ].…”

“…According to previous anatomical studies, an isthmus is present in the thyroid gland in 92.5% of adults and it is 11.1 ± 6.2 cm × 15.9 ± 5.8 cm in size [ 8 , 9 ]. In addition, a pyramid is present in 38.7–52.5% of adults and is approximately 22.6 cm × 11.2 cm in size [ 11 – 15 ].…”

“…These findings led to speculation that the incidence of postoperative hypothyroidism would be reduced if a sufficiently large volume of the thyroid gland is preserved. In a previous study, the surgeons aimed to increase the residual thyroid volume by preserving the entire isthmus during conventional thyroid lobectomy [ 8 ]. The authors concluded that postoperative hypothyroidism following conventional thyroid lobectomy appears to be very rare when the isthmus is preserved.…”